Surface mount technology is a technology for mounting electrical and electronic components to a printed circuit board. In many cases, the electronic components that are mounted on the printed circuit board are arranged in packages having conductive pins. The package is often in the form of a housing in which digital electronic devices, processors, transistors, and groups of analog devices are contained.
The surface mount process includes placing such component packages on predetermined locations on the printed circuit board such that the conductive pins contact predetermined traces on the printed circuit board. The board then undergoes a soldering process, such as an infrared (IR) reflow process, which distributes solder to electrically and physically connect pins of the packages onto conductors on the printed circuit board at the predetermined locations.
Dual in-line surface mount packages are a form of surface mount package that includes a case or container and two rows of surface mount pins or leads. The case can contain a chip, passive electrical components and/or RF components, among things. One type of package can include small coils, which are used for chokes or transformers. Such devices include one or more conductive coils wrapped around a toroidal core. The ends of the wires are typically electrically connected to respective surface mount pins, to allow circuit connection through the devices. The pins, in turn, are soldered to conductive traces on the printed circuit board as discussed above.
Such devices are known, but can have issues during circuit board assembly that lead to unreliability. Other known devices require manufacturing steps that can lead to damage, or are otherwise complex and costly.
One known device for housing transformers in a surface mount package is an open bottom transformer case disclosed in U.S. Pat. No. 5,656,985 to Lu. U.S. Pat. No. 5,656,985 shows a surface mount package including transformers in an open bottom molded package. The coils of the transformers are connected to dual-in-line pins, which have been bent in a gull wing design. The pins are molded into the case, but are then subject to multiple bends after molding. The long, gull-wing shaped pin can be prone to damage because of the length of metal that is cantilevered from the body of the case. Such damage can occur before or during placement.
Other designs have been proposed, but which contain similar drawbacks, and/or introduce even more complexity in the manufacturing process.